Liquid crystal display apparatus

ABSTRACT

A liquid crystal display apparatus comprises:  
     a color filter base plate having a transparent substrate, a black matrix and a colored film of three primary colors provided on the transparent subsrate,  
     an electrode-carrying base plate provided with electrodes for applying an electric field parallel to the color filter,  
     and a liquid crystal disposed therebetween,  
     wherein a spacer is formed on the black matrix by patterning a resin.  
     The color filter facilitates production of a liquid crystal display apparatus.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a liquid crystal displayapparatus driven by electric fields parallel to a base plate and a colorfilter for use in the liquid crystal display apparatus.

[0003] 2. Description of the Related Art

[0004] As described in some detail later with reference to FIG. 2,conventional color liquid crystal display apparatuses of, for example,twisted nematic TN (twisted nematic) mode and IPS (in-plain switching)mode (lateral electric field method) normally employ glass fibers orplastic beads as a spacer between a color filter-side base plate and anelectrode base plate provided with thin film transistors (TFTs) and aplurality of scan electrodes, in order to maintain the thickness of theliquid crystal layer (cell gap). The spacer such as a plurality ofplastic beads is provided by spraying, so that the arrangement ofindividual spacer elements is uncontrollable, thereby causing problemsof deterioration of the display quality of a liquid crystal displaydevice due to light scattering by the spacer elements present on pixels.

[0005] Liquid crystal display devices employing sprayed spacer elements,such as plastic beads, also have the following further drawbacks. Sincethe spacer elements have spherical or rod-like shapes, the spacerelements form point-like or line or like contacts during the pressing ofan assembly of base plates into a cell and, therefore, may well break analignment layer or a transparent electrode in the device, possiblyresulting in a display defect. Breakage of an alignment layer or atransparent electrode will also contaminate the liquid crystal andresult in a voltage decrease.

[0006] Furthermore, a step of uniformly spraying spacer elements isrequired, or high-precision control of particle size distribution of thespacer elements is required. Thus, it is difficult to provide a liquidcrystal display device having a stable display quality by a simplemethod.

[0007] Particularly in IPS mode liquid crystal display apparatuses,there is a need to maintain a cell gap with an increased consistency,thereby requiring an increased number of spacer spraying steps. The IPSmode liquid crystal display apparatuses also suffer more remarkably fromthe aforementioned problems in that for example, due to its material,the alignment layer may be fragile and conspicuous light scatter by thespacer may occur due to the increased back light intensity.

[0008] To solve these problems, JP-A-63-82405, JP-A-04-93924, andJP-A-07-318950 propose a spacer structure wherein two or three coloredlayers are laminated. However, in TN-type liquid crystal displayapparatuses, in order to prevent a short circuit between transparentelectrodes in a portion where the spacer contacts a counter base plateand electrodes in the counter base plate, there is a need to form aninsulating film in an upper portion of the counter base plate or thespacer or a need to restrict the position where the spacer is formed orthe size of the spacer, thereby making production of a liquid crystaldisplay apparatus difficult.

SUMMARY OF THE INVENTION

[0009] Accordingly, the present invention seeks to provide a colorliquid crystal display apparatus that is easy to produce and excellentin display quality with a high contrast and a wide visual field angle.

[0010] Thus, the present invention provides a liquid crystal displayapparatus comprising:

[0011] a color filter base plate having a transparent substrate, a blackmatrix and a colored film of three primary colors provided on thetransparent substrate,

[0012] an electrode-carrying base plate provided with electrodes forapplying an electric field parallel to the color filter,

[0013] and a liquid crystal disposed therebetween,

[0014] wherein a spacer is formed on the black matrix by patterning aresin.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Preferred embodiment of the present invention will be describedin detail hereinafter with reference to the accompanying drawings, inwhich:

[0016]FIG. 1 is a schematic sectional view of a color liquid crystaldisplay apparatus according to an embodiment of the present invention;and, for comparison

[0017]FIG. 2 is a sectional view of a conventional color liquid crystaldisplay apparatus.

[0018] Referring firstly to FIG. 2, a known color filter for use in aliquid crystal display apparatus comprises a transparent substrate 1carrying, on its upper surface, a black matrix 2. Disposed above andspaced from the transparent substrate 1 is an upper substrate 1, from alower surface of which project gate electrodes 9 and a common electrode12. An insulating film 9 covers and is profiled to be in face to facecontact with the downwardly facing surface and gate and commonelectrodes 9 and 12.

[0019] Each of a drain electrode 10, source electrode 11 and thin filmtransistor 13 depend downwardly from the insulating film 8. Thisarrangement of electrodes 9-12 is designed to apply an electrode fieldparalled to the color filter. A profiled protective film 7 covers andlies in face to face contact with the insulating film 8 and drain andsource electrode 10 and 11. The protective film 7 is in turn covered byan alignment layer 6. A gap therefore exists between upwardly facingblack matrix 2 on transparent substrate 1 and downwardly facingalignment layer 6 on upper substrate 1. In this gap sits a liquidcrystal 14. In this known color filter, the gap is maintained by aplurality of beads 6.

[0020] Referring now to FIG. 1, a liquid crystal display apparatusembodying the invention has all of the components described above withreference to FIG. 2, except that the gap in which sits the liquidcrystal 14 is maintained not by beads 6, but by respective color layers3, 4 and 5, being respective blue, green and red layers stacked oneabove the other.

DETAINLED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] More particularly, the color filter used in the present inventionhas a transparent substrate, and a black matrix formed by patterning alight-shielding material. Openings in the black matrix are covered withpixels formed by colored layers provided in desired patterns separatelyfor each color employed. The number and types of colors to be employedmay be chosen at will. Spacer elements are formed on the black matrix bypatterning a resin. The color filter may further have an overcoat layerthat is formed on the colored layers if necessary. The color filter isused in a color liquid crystal display apparatus driven by electricfields parallel to the transparent base plate (lateral electric fields).This type of color liquid crystal display apparatus does not require acommon electrode provided on the side of the color filter base plate,unlike a normal TN mode color liquid crystal display apparatus.Therefore, even though the spacer formed on the color filter base platecontacts the counter base plate, there is no short circuit between thecommon electrode and pixel electrodes or wiring on the counter baseplate. The restrictions on the size of the spacer are therefore reduced.Further, the need to provide an insulating film on the side of thecounter base plate is eliminated. Thereby, production of the liquidcrystal display apparatus is facilitated because the number of man hoursis reduced and the processing precision is improved. Furthermore, forthe lateral electric field liquid crystal display apparatuses, whichrequire control of a cell gap between the base plates with an increasedprecision, the color filter having a spacer formed by patterning isespecially suitable because spacer elements having consistent heightsand sizes can be uniformly arranged in the base plate, thereby making itpossible to provide a uniform cell gap. The resin layer forming thespacer may be a single layer, or a plurality of laminated layers if asingle layer fails to provide a sufficient height.

[0022] The resin layer forming the spacer according to the presentinvention is preferably formed of a material capable of bearing loadsduring production of a liquid crystal panel. Preferable examples of sucha material are photosensitive or non-photosensitive materials such aspolyimide-based resin, epoxy-based resin, acrylic resin, urethane-basedresin, polyester-based resin and polyolefin-based resin.

[0023] There are several types of photosensitive resin, for example,photodegradable resin, photo crosslinking resin and photopolymerizingresin. Particularly preferred in a color filter embodying the presentinvention are, for example, photosensitive compositions such asphotosensitive polyamic acid compositions, containing monomers,oligomers or polymers having ethylene unsaturated bonds and an initiatorthat generates radicals in respective to ultraviolet rays.

[0024] As for the non-photosensitive resin, resins enabling image orpattern development are preferably used. The non-photosensitive resinused in the present invention preferably has resistance to heat appliedduring the process for producing the liquid crystal display apparatusand also preferably has resistance to any organic solvent used duringthe process for producing the liquid crystal display apparatus.Polyimide-based resin is more preferably used, due to its highresistance to heat and organic solvents and its excellent mechanicalproperties for use as a spacer.

[0025] The polyimide resin used to prepare a spacer in a liquid crystaldisplay apparatus embodying the present invention may be a resinobtained by applying to a substrate solution of a polyimide precursorand subjecting it to heat treatment, whereby a polymer (polyimide,polyamideimide) having imide rings or other cyclic structures isproduced. The polyimide precursor may be a poly (amic acid) containing astructure unit (I) as a main component (ie no other structure unit ispresent in a greater molar proportion), which structure unit (I) has theformula

[0026] The polyimide-based resin may have bonds other than imide bonds,such as amide bonds, sulfone bonds, ether bonds and carbonyl bonds,without causing any significant drawback.

[0027] In the general formula (1), n is 1-2, and R₁ is a trivalent ortetravalent organic group having at least two carbon atoms. For improvedheat resistance, R₁ is preferably a trivalent or tetravalent grouphaving a cyclic hydrocarbon, an aromatic ring or an aromaticheterocyclic ring in which the number of carbon atoms is 6 to 30.Examples of R₁ are a phenyl group, biphenyl group, terphenyl group,naphthalene group, perylene group, diphenyl ether group, diphenylsulfone group, diphenyl propane group, benzophenone group, biphenyltrifluoropropane group, cyclobutyl group and a cyclopentyl group.However, R₁ is not limited to these groups. R₂ is a bivalent organicgroup having at least two carbon atoms. For improved heat resistance, R₂is preferably a bivalent group having a cyclic hydrocarbon, an aromaticring or an aromatic heterocyclic ring in which the number of carbonatoms is 6 to 30. Examples of R₂ may be a phenyl group, biphenyl group,terphenyl group, naphthalene group, perylene group, diphenyl ethergroup, diphenyl sulfone group, diphenyl propane group, benzophenonegroup, biphenyl trifluoropropane group, diphenyl methane group and acyclohexyl methane group. However, R₂ is not limited to these groups. Inthe polymer containing as a main component the structure unitrepresented by general formula (1), each of R₁ and R₂ may be formed byone of these groups or may be a copolymer formed by two or more of thesegroups. In order to increase the adhesion to a substrate, it is possibleto copolymerize with, for example, bis-(3-aminopropyl)tetramethyldisiloxane having a siloxane structure, as a diamine component in anamount within a range that will not reduce the heat resistance. It isalso possible to add, as an amino terminal sealer, an anhydride such asmaleic anhydride, in an amount in accordance with the concentration ofterminals after polymerization of a polyimide precursor, and allow it toreact.

[0028] The mechanical properties of the polyimide film become betterwith increasing molecular weight. Therefore, it is desirable that apolyimide precursor have a large molecular weight. However, if apolyimide precursor is subjected to wet etching for patterning, anexcessively large molecular weight of the polyimide precursor results inan inconveniently long development time. Therefore, it is normallypreferred that the degree of polymerization be within a range of 5 to1000.

[0029] The resin that forms the spacer may contain a coloring agent ifnecessary. As a coloring agent, an organic pigment, an inorganic pigmentor a dye may be used. It is further possible to add various additives,such as an ultraviolet absorbing agent or a dispersion agent, a levelingagent. If the spacer needs to have a light-shielding characteristic, itis possible to use a light shielding agent, such as carbon black, powderof a metal oxide such as titanium oxide or iron tetroxide, metal sulfidepowder, metal powder, and further a mixture of pigments of, for example,red, blue and green color. Among these, carbon black has an excellentlight shielding characteristic and therefore is particularly preferred.If the spacer needs to have an insulating characteristic as well as alight shielding characteristic, it is possible to use carbon black whosesurfaces are coated with fine particles of an insulating inorganiccompound such as titanium oxide or iron oxide.

[0030] In a liquid crystal display apparatus embodying the presentinvention, it is preferable that the spacer be formed in non-displayareas inside and outside the display screen area. In this manner, theinterval between the two base plates of the liquid crystal displaydevice can be more consistently maintained within the display apparatusscreen.

[0031] The spacer, formed by patterning the resin layer according to thepresent invention, is preferably formed by laminating a colored layerthat covers the open portions of the matrix, more preferably, bylaminating layers of three primary colors. By forming the spacer bylaminating a colored layer, the spacer can be formed simultaneously withproduction of a color filter without increasing the number of processingsteps. Furthermore, by lamination of three primary color layers, itbecomes easy to provide a sufficient cell gap without increasing thefilm thickness of each colored layer. If lamination of three primarycolor layers does not provide a sufficient height, an additional resinlayer may be laminated.

[0032] A liquid crystal display apparatus according to the presentinvention has light shielding areas arranged between individual pixels,called a “black matrix”. With the black matrix provided, the colorfilter improves the contrast of the liquid crystal display apparatus.

[0033] As a black matrix, thin metal films (having a thickness of about0.1-0.2 μm) of, eg Cr, Al or Ni or resin black matrixes wherein a lightshielding agent is dispersed in a resin are normally employed. In thepresent invention, it is more preferable to use a resin black matrixformed by dispersing a black pigment in a polyimide film. This isbecause such a resin black matrix has a low reflectivity and a good heatresistance and a good solvent resistance and, moreover, has a lowrelative dielectric constant so that it causes less disturbance to thelateral electric fields. Furthermore, it is possible to provide theresin black matrix with a capacity for orienting liquid crystal byrubbing as performed on the pixels.

[0034] Furthermore, resin black matrixes are easy to increase inthickness compared with metal thin films, so that it is easier to form aspacer that provides a sufficient cell gap by forming a spacer on aresin black matrix.

[0035] Examples of the light shielding agent usable in the black matrixare carbon black and a powder of a metal oxide such as titanium oxide oriron tetroxide, metal sulfide powder, metal powder, and also a mixtureof pigments of, for example, red, blue or green color. Among these,carbon black has an excellent light shielding characteristic andtherefore is particularly preferred. Since carbon black having smallparticle diameters and therefore good dispersibility normally exhibits abrownish color tone, it is preferred to mix such carbon black with apigment of complementary color to render it black.

[0036] If the black matrix is formed of a polyimide resin, it isnormally preferred to use, as a black paste solvent, an amide-familypolar solvent such as N-methyl-2-pyrrolidone, N,N-dimehtylacetoamide orN,N-dimethylformamide or a lactone-family polar solvent such asγ-butylolactone.

[0037] The method for dispersing carbon black or a light shielding agentsuch as a pigment of complementary color to the carbon black may be, forexample, a method wherein after a light shielding agent and, forexample, a dispersing agent are mixed into a polyamide precursorsolvent, they are dispersed in a dispersing machine such as a three-rollmachine, a sand grinder or a ball mill. It is also possible to addvarious additives for providing improvements in the dispersion,application characteristic and leveling characteristic of the carbonblack.

[0038] The resin black matrix may be produced by applying a black pasteon the transparent substrate, drying the paste and then patterning. Theblack paste may preferably be applied by, for example, a dip method, aroll coater method, a spinner method, a die coating method or a methodusing a wire bar. After being applied, the paste may be heated and dried(semi-cured) using an oven or a hot plate. The semi-cure conditions varydepending on the resin and solvent used, and the amount of pasteapplied. It is normally preferred to heat the paste at 60-200° C. for1-60 minutes.

[0039] If the resin of the black paste coating thus formed is anon-photosensitive resin, a positive photoresist coating is formedthereon before exposure and development. If the resin is aphotosensitive resin, the black paste coating is exposed and developedimmediately or after an oxygen blocking film is formed. Then, after thepositive photoresist or the oxygen blocking film (if necessary) isremoved, the developed coating is subjected to heating and drying (maincure). In a case where a polyimide-based resin is obtained from aprecursor, the main cure conditions slightly vary depending on theamount of paste applied. Normally, the coating is heated at 200-300° C.for 1-60 minutes. Through these processes, a black matrix is formed on asubstrate.

[0040] It is also possible to form a resin black matrix by a so-calledtransfer method. In this method, a transfer film wherein a black layerprovided with a photosensitive component is formed on a base is preparedbeforehand, and the film is laid on a substrate (heated and pressurizedif necessary) for exposure and development. After that, the base ispeeled leaving a resin black matrix formed on the substrate.

[0041] The film thickness of the resin black matrix is preferably0.5-2.0 μm and, more preferably, 0.8-1.5 μm. If the film thickness ofthe resin black matrix is less than 0.5 μm, it becomes difficult toreliably provide a sufficient cell gap and, further, the light shieldingcharacteristic becomes insufficient. If the film thickness is greaterthan 2.0 μm, it becomes likely that the flatness of the liquid crystaldisplay apparatus will be sacrificed, resulting in a stepped orirregular surface, although a sufficient cell gap may be reliablyprovided.

[0042] The light shielding characteristic of the resin black matrix maybe represented by an OD value (common logarithm of the inverse oftransmittance). To improve display quality of the liquid crystal displayapparatus, the OD value is preferably 2.5 or higher and, morepreferably, 3.0 or higher. The upper limit of the OD value should bedetermined based on the relationship with the aforementioned preferablerange of the film thickness of the resin black matrix.

[0043] The reflectivity of the resin black matrix is preferably 2% orlower in terms of the reflectivity (Y value) corrected by a visibilityfactor within a visual light range of 400-700 nm and, more preferably,1% or lower.

[0044] Each opening in the black matrix is normally 20-200 μm×20-300 μm.The colored layer is formed such that such open portions in the blackmatrix are covered.

[0045] The colored layer in a liquid crystal display apparatus embodyingthe present invention is a layer formed by a film having a capacity fortransmitting any selected color of light. The colored layer may beformed of any material. Normally, a liquid crystal display apparatusaccording to the present invention includes at least three layers ofthree primary colors, that is, red (R), green (G) and blue (B), or cyan(C), magenta (M) and yellow (Y), and each pixel is provided with one ofthe three colored layers. Examples of specific materials for the coloredlayer are a polyimide film wherein a coloring agent, a pigment or a dyeis dispersed, a PVA (polyvinyl alcohol) treated with staining or a SiO₂film whose thickness has been controlled so that only selected light istransmitted. A polyimide film wherein a pigment is dispersed is morepreferable because the polyimide film makes it possible to form acolored layer through a process comparable with or easier than theprocesses required for other materials and, moreover, the polyimide filmis better in heat resistance, light resistance and chemical resistance.Furthermore, employment of the polyimide film is preferred for improvedmechanical properties in a case where the colored layer is used as aspacer.

[0046] The relative dielectric constant of the colored layer accordingto the present invention is preferably less than 4.5 and, morepreferably, 3.6 or less. To effectively apply electric fields to theliquid crystal in a direction parallel to the base plate, it isdesirable that the relative dielectric constant of the colorfilter-constituting materials be less than either the shorter axiscomponent or the longer axis component of the relative dielectricconstant of the liquid crystal, more preferably, ½ or less. This isbecause with an increase in the relative dielectric constant of thecolor filter-constituting materials, the deviation of the direction ofan electric field from the direction parallel to the base plate at theinterface between the liquid crystal and the color filter increases, sothat the effective electric field decreases and, therefore, the liquidcrystal switching efficiency decreases. For a color filter without anovercoat, the colored layer is preferably formed of a material having areduced relative dielectric constant because then the colored layercontacts the liquid crystal directly or with an alignment layer providedtherebetween. For a color filter having an overcoat, it is alsopreferred that the colored layer be formed of a material having areduced relative dielectric constant so as to achieve a reduction of therelative dielectric constant of the entire color filter.

[0047] The maximum component of the relative dielectric constant of theliquid crystal used in liquid crystal display apparatuses driven by thinfilm transistors is normally about 8-12 or at least 4.5. Therefore, therelative dielectric constant of the colored layer is preferably lessthan 4.5 and, more preferably, 3.6 or less. The relative dielectricconstant herein refers to values measured at 20° C. within a frequencyof 100 Hz-100 kHz.

[0048] The colored layer according to the present invention is morepreferably a film provided with a capacity for orienting liquid crystalmolecules in contact therewith by an orientation method such as rubbing,hereinafter referred to as an “alignment layer”. Thereby, it becomespossible to omit a step of separately applying an alignment layer on acolor filter during production of a liquid crystal display panel.

[0049] It is desirable that the colored layer according to the presentinvention have a surface that is smooth as much as possible. Morespecifically, the colored layer surface desirably has an Ra value of0.010 μm or lower, the Ra value being a measured value indicating asurface roughness. This level of surface roughness will preventoccurrence of an orientation failure during rubbing and thereforeprevent a display failure caused by an orientation failure.

[0050] Pigments used in the present invention are not particularlylimited. Preferred are pigments excellent in light resistance, heatresistance and chemical resistance. Specific examples of representativepigments are cited below with reference to their Color Index (CI)numbers. Examples of yellow pigments are CI Pigment Yellow 20, 24, 83,86, 93, 94, 109, 110, 117, 125, 137, 138, 139, 147, 148, 153, 154, 166and 173. Examples of orange pigments are CI Pigment Orange 13, 31, 36,38, 40, 42, 43, 51, 55, 59, 61, 64 and 65. Examples of red pigments areCI Pigment Red 9, 97, 122, 123, 144, 149, 166, 168, 177, 180, 192, 215,216 and 224. Examples of purple pigments are CI Pigment Violet 19, 23,29, 32, 33, 36, 37 and 38. Examples of blue pigments are CI Pigment Blue15 (eg. 15:3, 15:4 and 15:6), 21, 22, 60 and 64. Examples of greenpigments are CI Pigment Green 7, 10, 36 and 47. An example of a blackpigment is CI Pigment Black 7. It is also possible to use pigmentssubjected to surface treatment such as rosin treatment, acidic grouptreatment and basic group treatment if desired.

[0051] A colored layer may be formed by applying to a substrate on whicha black matrix has been formed, and then drying and patterning. Themethod for dispersing or dissolving a coloring agent such as a pigmentmay be, for example, a method wherein after a resin and a coloring agentare mixed into a solvent, the resin and coloring agent are dispersed ina dispersing machine such as a three-roll machine, a sand grinder or aball mill.

[0052] The colored paste is preferably applied, as in application of ablack paste, for example, by a dip method, a roll coater method, aspinner method, a die coating method or a method using a wire bar. Afterbeing applied, the paste may be heated and dried (semi-cured) using anoven or a hot plate. The semi-cure conditions vary depending on theresin and solvent used, and the amount of paste applied. It is normallypreferred to heat the paste at 60-200° C. for 1-60 minutes.

[0053] If the resin of the colored paste coating thus formed is anon-photosensitive resin, a positive photoresist coating is formedthereon before exposure and development. If the resin is aphotosensitive resin, the colored paste coating is exposed and developedimmediately or after an oxygen blocking film is formed. Then, after thepositive photoresist or the oxygen blocking film (if necessary) isremoved, the developed coating is subjected to heating and drying (maincure). The main cure conditions vary depending on the resin. However, ina case where a polyimide-based resin is obtained from a precursor, thecoating is normally heated at 200-300° C. for 1-60 minutes. Throughthese processes, a patterned colored layer is formed on the substratecarrying the black matrix formed thereon.

[0054] After a first color layer is formed over the entire surface ofthe substrate carrying the black matrix, unnecessary portions may beremoved by photolithography, thereby forming a desired pattern of thefirst color layer. The second and third color layers may be formed bysimilar procedures into desired color layer patterns.

[0055] In the color filter of the present invention, it is possible toprovide an overcoat film on the colored layer if desired. The overcoatfilm herein is a film formed for protection of the colored layers or theflattening of the color filter surface. In an IPS mode liquid crystaldisplay apparatus, the overcoat film will achieve an advantage ofshielding an electrically conductive material, such as a metal blackmatrix, so as to effectively apply lateral electric fields to the liquidcrystal. As in the colored layers, the overcoat film is more preferablya film provided with a capacity for orienting liquid crystal moleculesin contact therewith by an orientation method such as rubbing. Thereby,it becomes possible to produce a liquid crystal display apparatuswithout a need to separately form an alignment layer on the colorfilter, thereby reducing the number of production processes. Further, inthe color filter of the present invention, the overcoat film will beeffective in improving the physical properties of the spacer. Moreover,it will become possible to adjust the height of the spacer by renderingthe overcoat film thickness over the display area less than the overcoatfilm thickness over the spacer.

[0056] Specific examples of the overcoat film may be inorganic films of,for example, SiO₂, and organic films such as epoxy films, acrylic epoxyfilms, acrylic films, siloxane polymer films, polyimide films,silicon-containing polyimide films and polyimide siloxane films.Preferred are polyimide-based high molecular weight films, such aspolyimide films, silicon-containing polyimide films and polyimidesiloxane films, due to their excellent flatness, applicability and heatresistance and, furthermore, their superiority over the other films intheir capacity for restricting the orientation of the liquid crystal.

[0057] The polyimide siloxane film according to the present inventionmay be a film produced by heat-treating a polyimide siloxane precursorcoating. The polyimide siloxane precursor coating can be produced byvarious procedures. In a representative procedure, a silicon compoundhaving in its molecule at least one primary amino group or at least onesecondary or higher alkoxide group is reacted with a tetracarboxylicdianhydride in an organic solvent, thereby producing a precursorcoating. The reaction product may further be hydrolyzed and condensed toproduce a precursor coating.

[0058] The overcoat film in a color filter embodying the presentinvention preferably has a surface that is smooth as much as possible.More specifically, the overcoat film surface desirably has an Ra valueof 0.01 μm or lower, the Ra value being a measured value indicating asurface roughness. This level of surface roughness will preventoccurrence of an orientation failure during rubbing and thereforeprevent a display failure caused by an orientation failure.

[0059] The relative dielectric constant of the overcoat film in thepresent invention is preferably less than 4.5 and, more preferably, 3.6or less, for the same reason as stated above in conjunction with thecolored layer. In particular, it is preferred that the overcoat filmthat contacts with liquid crystal directly or with an alignment layerprovided therebetween be formed by a material having a further reducedrelative dielectric constant. The relative dielectric constant hereinrefers to a value measured at 20° C. with a frequency of 100 Hz-100 kHz.

[0060] The overcoat may preferably be applied, as in application of ablack paste, by, for example, a dip method, a roll coater method, aspinner method, a die coating method or a method using a wire bar. Afterapplication, heating and drying (semi-cure) may be performed using anoven or a hot plate. The semi-cure conditions vary depending on theresin and solvent used, and the amount applied. It is normally preferredto heat it at 60-200° C. for 1-60 minutes.

[0061] The thus-formed overcoat film may then heated and dried(main-cured). The main cure conditions vary depending on the resin. If apolyimide-based resin is obtained from a precursor, the overcoat film isnormally heated at 200-300° c. for 1-60 minutes. Through theseprocesses, the overcoat film is formed.

[0062] The orientation treatment in the present invention may beperformed by any method as long as the method provides the coloredlayers or the overcoat film with capacity for orienting liquid crystalin contact therewith. Specific examples of such method are a rubbingmethod, an oblique vapor deposition method and a grating method. Amongthese, a rubbing method is more preferably used because the method canbe performed by a relatively simple apparatus so as to provide a highproductivity on an industrial scale, and can provide a high orientatingcapacity.

[0063] The rubbing method used in preparing a color filter embodying thepresent invention is a method wherein a cloth (for example) is rubbed ina single direction against a film, that is, the object of orientationtreatment. The liquid crystal molecules that contact with therub-treated film are oriented in the rubbing direction. The material tobe rubbed against the film varies depending on the hardness of the filmto be treated. For a polyimide film, a cotton cloth or a rayon clothhaving a staple length of 2-3 mm is normally used.

[0064] The color filter of the present invention preferably has anelectrically conductive transparent film provided on the reverse face ofa base plate. The reverse face of the base plate is that face oppositefrom the face that contacts with the liquid crystal when a liquidcrystal display apparatus is assembled. With the electrically conductivetransparent film provided on the reverse face of the base plate, thecharging of the base plate can be prevented. Charges in the base platecan cause deficiencies or problems such as a defective conveyance of thebase plate during production processing steps, deposition ofcontaminants due to static electricity and breakage of thin filmtransistors in the counter base plate. Furthermore, an electric fieldcaused by static electricity may disturb the orientation of the liquidcrystal inside the cell and thereby cause a display defect. Examples ofthe electrically conductive transparent film employed in the presentinvention are an electrically conductive transparent film formed mainlyfrom a metal or a metal oxide, or an electrically conductive transparentfilm formed mainly from an alloy of a combination of several kinds ofmetals and metal oxides.

[0065] Specific examples of a main component of the electricallyconductive transparent film are metals and metal oxides such as Al, Mo,Cr, Ta, Cu, W, Ti, Au, Te, TeSe, In, Ge, Tb, Dy, Gd, ZnS, TbFe, DyFe,Gd, SiO₂, SiO, SiC, SI₅N₄, AlN, ITO, In₂O₃, SnO₂, ZnO, ZnS, CaS, SrS,Ta₂O₅, WO₃, Y₂O₃, SrTiO₃, BaTiO₃, PbTiO₃, Al₂O₃, NiCr, TaSiO₂ andTiCSiO₃. Practically, alloys of combinations of several species of thesemetals and metal oxides may be used. Among these, ITO is preferably usedbecause it does not sacrifice the transparency and is excellent inelectric conductivity.

[0066] The specific resistance of the electrically conductivetransparent film is normally 2 kΩ·cm or less and, preferably, 600 Ω·cmand, more preferably, 300 Ω·cm. If the specific resistance of theelectrically conductive transparent film is excessively great, asufficient charge preventing effect may not be achieved.

[0067] The transmittance of the electrically conductive transparent filmaccording to the present invention is preferably 96% or higher and, morepreferably, 98% or higher. If the transmittance of the electricallyconductive transparent film is lower, the transmittance of the colorfilter may become inconveniently low and the contrast also decreases toan undesirable level.

[0068] The thickness of the electrically conductive transparent film ina color filter embodying the present invention is preferably 10 nm to100 nm and, more preferably, 20 nm to 50 nm. If the thickness of theelectrically conductive transparent film is excessively small, asufficient charge preventing effect may not be achieved. If the filmthickness is excessively great, the transmittance may decrease to anundesired level.

[0069] An example of the method for forming a spacer through laminationof colored layers in a color filter according to the present inventionwill be described below.

[0070] After a first color layer is formed over the entire surface ofthe base plate carrying the resin black matrix formed thereon,unnecessary portions are removed by photolithography, thereby forming adesired pattern of the first color layer. Portions of the colored layerthat cover openings in the resin black matrix and that form spacerelements through lamination of colored layers are left on the baseplate. The second and third color layers are formed and left on the baseplate by similar procedures, so that the openings in the resin blackmatrix are covered with one of the three colored layers and the threelayers are left to provide spacer elements. The colored layers over theopenings and the colored layers forming the spacer elements may becontinuous or separate from each other.

[0071] The thickness of the three primary color layers is notparticularly limited. However, the thickness of each layer is preferably1-3 μm, so that the total thickness of the three layers amounts to 3-9μm. If the total film thickness is less than 3 μm, a sufficiently largecell gap may not be obtained. If the total film thickness exceeds 9 μm,it may become difficult to uniformly apply the colored layers.

[0072] If the color filter of the present invention is used to maintaina cell gap in a case, for example, where R, G and B are selected as thethree colors, the cell gap for R in the liquid crystal display apparatuscorresponds to the film thickness of G+B+Bk (resin black matrix), andthe cell gap for G corresponds to the film thickness of B+R+Bk, and thecell gap for B corresponds to a film thickness of R+G+Bk. If thedispersibility of the coloring agents in the pastes for forming thecolored layers is improved or if the leveling characteristic is improvedfor the purpose of uniform application, the height of the spacer formedby lamination of the three primary color layers becomes less than thetotal film thickness of the three color layers over pixels. That is, thecell gap for R becomes less than the total thickness of G+B+Bk, and,likewise, the cell gap for G becomes less than the total thickness ofB+R+Bk, and the cell gap for B becomes less than the total thickness ofR+B+Bk.

[0073] The spacer formed by lamination of the three primary color layersaccording to the present invention is formed on the resin black matrixas described above. The areas and locations of spacer elements on theblack matrix are strongly dependent on the structure of the activematrix base plate that faces the color filter when a liquid crystaldisplay device is produced. If no such restriction is imposed by thecounter electrode base plate, the areas and locations of the spacerelements are not particularly limited. However, considering the pixelsize, the area of each spacer element is preferably 10 μm² to 1000 μm².If the area of each spacer element is less than 10 μm², it may becomedifficult to form a minute and precise pattern and laminate. If it isgreater than 1000 μm², it may become difficult to arrange the spacerelements precisely on the black matrix, depending on the configurationof the spacer elements.

[0074] The liquid crystal display apparatus of the present invention hasan excellent feature namely that of a wide view field angle, because itis driven by lateral electric fields. Moreover, since no spacer existsin the pixels, deterioration of the display quality caused by lightleakage through the spacer or light scatter thereby are eliminated.Furthermore, since the liquid crystal display apparatus has fixed spacerelements that are formed and regularly arranged by patterning the resinlayers, the cell gap becomes uniform, thereby improving the displayquality. Thus, the present invention makes it easy to provide a TFTliquid crystal display apparatus with a wide view field angle and animproved display quality. Further, since thin film transistors (TFTs)are provided in the electrode-carrying base plate, it becomes possibleto produce a TFT liquid crystal display apparatus further improved indisplay quality.

EXAMPLE 1

[0075] [Production of Black Matrix]

[0076] 3,3′,4,4′-Biphenyl tetracarboxylic dianhydride,4,4′-diaminodiphenyl ether and bis(3-aminopropyl)tetramethyl disiloxanewere reacted in a solvent of N-methyl-2-pyrrolidone, thereby obtaining apolyimide precursor (polyamic acid) solution.

[0077] A carbon black mill base having the following composition wasdispersed at 7000 rpm for 30 minutes using a homogenizer. Glass beadswere filtered out, thereby preparing a black paste. <Carbon mill base>Carbon black (MA100 by Mitsubishi  4.6 parts Kasei Kabushiki Gaisha)Polyimide precursor solution 24.0 parts N-methyl pyrrolidone 61.4 partsGlass beads 90.0 parts

[0078] The black paste was applied to a no-alkali glass (OA-2 by NipponDenki Glass Kabushiki Gaisha) substrate having a size of 300×350 mmusing a spinner. The applied paste was semi-cured at 135° C. in an ovenfor 20 minutes. A positive resist (Shipley “Microposit” RC100 30 cp) wasthen applied using a spinner, after which the resist was dried at 90° C.for 10 minutes. The resist film thickness was 1.5 μm. The positiveresist was then exposed through a photomask using an exposure apparatusPLA-501F by Canon Kabushiki Gaisha.

[0079] The substrate was dipped in a developer aqueous solution at 23°C. The aqueous solution contained 2% by weight of tetramethylammoniumhydroxide. The substrate was oscillated in such a manner that thesubstrate reciprocated over a distance of 10 cm once in every fiveseconds, thereby simultaneously performing development of the positiveresist and the etching of the polyimide precursor. The development timewas 60 seconds. After that, the positive resist was peeled using methylcellosolve acetate. The substrate was then cured at 300° C. for 30minutes, thereby obtaining a resin black matrix. A spacer pattern wassimultaneously formed outside the screen area. The film thickness of theresin black matrix was 0.90 μm, and the OD value thereof was 3.0. Thereflectivity (Y value) at the interface between the resin black matrixand the glass substrate was 1.2%.

[0080] [Production of Colored Layers]

[0081] As red, green and blue pigments, a dianthraquinone-based pigmentindicated by Color Index No. 65300 Pigment Red 177, a phthalocyaninegreen-based pigment indicated by Color Index No. 74265 Pigment Green 36,and a phthalocyanine blue-based pigment indicated by Color Index No.74160 Pigment Blue 15-4 were prepared. These pigments were separatelymixed and dispersed in the polyimide precursor solution, therebyobtaining three colored pastes of red, green and blue.

[0082] The blue paste was first applied to the resin black matrixsubstrate, and dried by hot air at 80° C. for 10 minutes, and thensemi-cured at 120° C. for 20 minutes. After that, a positive resist(Shipley “Microposit” RC100 30 cp) was applied using a spinner, and thendried at 80° C. for 20 minutes. The positive resist was exposed througha mask and the substrate was then dipped in an alkaline developer(Shipley “Microposit” 351). The substrate was oscillated in thedeveloper, thereby simultaneously performing development of the positiveresist and the etching of the polyimide precursor. After that, thepositive resist was peeled using methyl cellosolve acetate. Thesubstrate was then cured at 300° C. for 30 minutes. The film thicknessin the colored pixel portion was 2.3 μm. Through patterning, blue pixelswere formed and, simultaneously, the first layer of the spacer over theresin black matrix was formed. The size of the spacer elements was 20μm×20 μm.

[0083] After the substrate was washed with water, the green paste wasapplied to form green pixels and the second layer of the spacer on theresin black matrix in a manner as described above. The film thickness inthe green pixel portion was 2.3 μm. The size of the spacer elements was20 μm×20 μm.

[0084] After the substrate was washed with water, the red paste wasapplied to form red pixels and the third layer of the spacer on theresin black matrix in a manner as described above. A color filter wasthus produced. The film thickness in the red pixel portion was 2.3 μm.The mask size of the spacer elements was 14 μm×14 μm.

[0085] The area of each spacer element formed on the resin black matrixby lamination of the colored layer was about 200 μm². The height of thespacer (that is, the thickness of the three colored layers on the resinblack matrix) was 5.6 μm, which is less than the total of the filmthicknesses of the individual colored layers (that is, 6.9 μm). Thespacer elements are provided inside the screen area at a rate of 1 pieceper pixel. Spacer elements of a laminate of the colored layers are alsoformed on portions of the frame-like resin black matrix portion in theperiphery of the screen area and on the spacer pattern formed by theblack paste outside the screen area in such a manner that the contactarea of these spacer elements with the counter base plate per unit areabecomes equal to that of the spacer elements inside the screen area.

[0086] The surface roughness of each colored layer was measured by asurface roughness tester, providing an Ra value of 0.006 μm.

[0087] [Measurement of Relative Dielectric Constant of Colored Layers]

[0088] An aluminum film of 1000 Å was vapor-deposited on a separatelyprepared non-alkali glass substrate using a vacuum vapor depositionapparatus, to produce common electrodes.

[0089] The red, blue and green color pastes as used for production ofthe color filter were separately spin-coated on aluminum films. Thepastes thus applied were then heated at 110° C. for 20 minutes and thenat 290° C. for 40 minutes in a clean oven, thereby forming polyimidecolored coatings having a film thickness of 1 μm.

[0090] A SUS mask having square holes of 1 cm×1 cm was laid over eachcolored layer film surface, and then subjected to aluminum vapordeposition, thereby forming counter electrodes.

[0091] After a portion of each colored layer was removed to form anelectrode lead-out portion, lead wires were connected to the counterelectrodes and the common electrodes using a silver paste.

[0092] The capacity between the common electrodes and the counterelectrodes were measured within a frequency range of 100 Hz-100 kHzusing an LCR meter. The polyimide film thickness and the counterelectrode area were also measured. Based on these measurements, therelative dielectric constant was calculated. The relative dielectricconstant in aforementioned frequency range was 4.3 or lower.

[0093] [Production of Color Liquid Crystal Display Device]

[0094] Direct rubbing was performed on the color filter. Anelectrode-carrying base plate equipped with thin film transistors (TFTs)was produced as described below.

[0095] First, gate and common electrodes were patterned on a non-alkaliglass substrate by photoetching using chrome. Then, insulating films ofsilicon nitride (SiN) were formed to cover the electrodes. Amorphoussilicon (a-Si) films were formed on the gate insulating films. On theamorphous silicon films, source and drain electrodes were formed usingaluminum. The electrodes were patterned so that electric fields willoccur between the common electrodes and the drain electrodes indirections parallel to the glass substrate. Protective films of SiN wereformed on the electrodes. Then, a polyimide-based alignment layer wasformed on the very top, and subjected to rubbing, thereby obtaining anelectrode-carrying counter base plate equipped with TFTs.

[0096] The color filter was fixed to the electrode-carrying base plateequipped with TFTs, using a sealant. A liquid crystal was then injectedthrough an injection opening formed in the seal, by leaving the emptycell under a reduced pressure, then dipping the injection opening into aliquid crystal tank, and then introducing a normal pressure. Afterinjection of the liquid crystal, the injection opening was sealed. Apolarizing plate was then fixed to the outside surface of the baseplate, thereby producing a cell. The liquid crystal display device thusproduced exhibited good display quality with a high contrast and nodisplay irregularity.

EXAMPLE 2

[0097] [Production of Color Filter]

[0098] By substantially the same procedure as in Example 1, a resinblack matrix and colored layers were sequentially patterned on anon-alkali glass substrate to produce a color filter provided with aspacer formed by lamination of the colored layers.

[0099] [Production of Color Liquid Crystal Display Device]

[0100] A polyimide-based alignment layer was formed on the coloredlayers of the color filter, and subjected to rubbing. Anelectrode-carrying base plate equipped with thin film transistors (TFTs)was produced by substantially the same procedure as in Example 1.

[0101] The color filter was fixed to the electrode-carrying base plateequipped with TFTs, using a sealant. A liquid crystal was then injectedthrough an injection opening formed in the seal, by leaving the emptycell under a reduced pressure, then dipping the injection opening into aliquid crystal tank, and then introducing a normal pressure. Afterinjection of the liquid crystal, the injection opening was sealed. Apolarizing plate was then fixed to the outside surface of the baseplate, thereby producing a cell. The liquid crystal display device thusproduced exhibited good display quality as in Example 1.

EXAMPLE 3

[0102] [Production of Color Filter]

[0103] By substantially the same procedure as in Example 1, a resinblack matrix and colored layers were sequentially patterned on anon-alkali glass substrate to produce a color filter provided with aspacer formed by lamination of the colored layers. The color filter wasspin-coated with a solution of a hardening composition obtained byreacting hydrolysates of γ-aminopropyl-methyldiethoxysilane with3,3′,4,4′-benzophenone tetracarboxylic dianhydride. The coated colorfilter was heated at 280° C. for three hours, thereby forming anovercoat film having a film thickness of 1 μm.

[0104] The surface roughness of the overcoat film was measured by asurface roughness tester, providing a measurement of 0.006 μm. Theovercoat film of the color filter was subjected to direct rubbing by arubbing device.

[0105] [Measurement of Relative Dielectric Constant of Overcoat Film]

[0106] An aluminum film of 1000 Å was vapor-deposited on a non-alkaliglass substrate using a vacuum vapor deposition apparatus, to producecommon electrodes.

[0107] The aluminum film was spin-coated with the overcoat solution usedto produce the color filter, and then heated at 280° C. for 3 hours,thereby forming an overcoat film having a film thickness of 1 μm. In aprocedure substantially the same as in the measurement of the relativedielectric constant of the colored layers in Example 1, the relativedielectric constant of the overcoat film was measured, providing arelative dielectric constant of 3.5 or lower in a frequency range of 100Hz-100 kHz.

[0108] [Production of Color Liquid Crystal Display Device]

[0109] The overcoat film of the color filter was subjected to directrubbing. An electrode-carrying base plate equipped with thin filmtransistors (TFTs) was produced by substantially the same procedure asin Example 1.

[0110] The color filter was fixed to the electrode-carrying base plateequipped with TFTs, using a sealant. A liquid crystal was then injectedthrough an injection opening formed in the seal, by leaving the emptycell under a reduced pressure, then dipping the injection opening into aliquid crystal tank, and then introducing a normal pressure. Afterinjection of the liquid crystal, the injection opening was sealed. Apolarizing plate was then fixed to the outside surface of the baseplate, thereby producing a cell. The liquid crystal display device thusproduced exhibited good display quality.

EXAMPLE 4

[0111] By substantially the same procedure as in Example 1, a resinblack matrix and colored layers were sequentially patterned on anon-alkali glass substrate to produce a color filter provided with aspacer formed by lamination of the colored layers. The color filter wasspin-coated with a solution of a hardening composition obtained byreacting hydrolysates of γ-aminopropyl-methyldiethoxysilane with3,3′,4,4′-benzophenone tetracarboxylic dianhydride. The coated colorfilter was heated at 280° C. for three hours, thereby forming anovercoat film having a film thickness of

[0112] [Production of Color Liquid Crystal Display Device]

[0113] A polyimide-based alignment layer was formed on the overcoat filmof the color filter, and subjected to rubbing. An electrode-carryingbase plate equipped with thin film transistors (TFTs) was produced bysubstantially the same procedure as in Example 1.

[0114] The color filter was fixed to the electrode-carrying base plateequipped with TFTs, using a sealant. A liquid crystal was then injectedthrough an injection opening formed in the seal, by leaving the emptycell under a reduced pressure, then dipping the injection opening into aliquid crystal tank, and then introducing a normal pressure. Afterinjection of the liquid crystal, the injection opening was sealed. Apolarizing plate was then fixed to the outside surface of the baseplate, thereby producing a cell. The liquid crystal display device thusproduced exhibited good display quality.

EXAMPLE 5

[0115] [Production of Color Filter]

[0116] An ITO film was formed on a surface of a non-alkali glasssubstrate by sputtering. The ITO film had a film thickness of 15 nm, aspecific resistance of 315 Ω·cm, and a transmittance of 99.6%. On asurface of the glass substrate opposite from the surface provided withthe ITO film, a resin black matrix and colored layers were sequentiallyformed by substantially the same procedure as in Example 1, therebyproducing a color filter provided with a spacer formed by lamination ofthe colored layers.

[0117] [Production of Color Liquid Crystal Display Device]

[0118] A polyimide-based alignment layer was formed on the coloredlayers of the color filter, and subjected to rubbing. Anelectrode-carrying base plate equipped with thin film transistors (TFTs)was produced by substantially the same procedure as in Example 1.

[0119] The color filter was fixed to the electrode-carrying base plateequipped with TFTs, using a sealant. A liquid crystal was then injectedthrough an injection opening formed in the seal, by leaving the emptycell under a reduced pressure, then dipping the injection opening into aliquid crystal tank, and then introducing a normal pressure. Afterinjection of the liquid crystal, the injection opening was sealed. Apolarizing plate was then fixed to the outside surface of the baseplate, thereby producing a cell. The liquid crystal display device thusproduced exhibited good display quality. Further, no display defectivedue to effect of static electricity was observed.

COMPARATIVE EXAMPLE 1

[0120] [Production of Color Filter]

[0121] A color filter was produced by sequentially patterning a resinblack matrix and colored layers on a non-alkali glass substrate insubstantially the same manner as in Example 1, except that a spacer of alaminate of the colored layers was not formed. The color filter wasspin-coated with a solution of a hardening composition obtained byreacting hydrolysates of γ-aminopropylmethyldiethoxysilane with3,3′,4,4′-benz ophenone tetracarboxylic dianhydride. The coated colorfilter was heated at 280° C. for three hours, thereby forming anovercoat film having a film thickness of 1 μm.

[0122] [Production of Color Liquid Crystal Display Device]

[0123] A polyimide-based alignment layer was formed on the overcoat filmof the color filter, and then subjected to rubbing. Anelectrode-carrying base plate equipped with thin film transistors (TFTs)was produced by substantially the same procedure as in Example 1.

[0124] Plastic beads having a diameter of 5 μm were sprayed onto thecolor filter and the color filter was then fixed to theelectrode-carrying base plate equipped with TFTs, using a sealant. Aliquid crystal was then injected through an injection opening formed inthe seal, by leaving the empty cell under a reduced pressure, thendipping the injection opening into a liquid crystal tank, and thenintroducing a normal pressure. After injection of the liquid crystal,the injection opening was sealed. A polarizing plate was then fixed tothe outside surface of the base plate, thereby producing a cell. Thecontrast of the thus-produced liquid crystal display device was lowerthan that of the liquid crystal display device provided with the coloredlayer-laminated spacer, due to light leakage and light scatter throughbeads and orientation defects caused by damage to the alignment layer.Moreover, display irregularity was considerable, probably caused by gapirregularity. Further, the TFT-carrying base plate was damaged by beadsduring the production process, resulting in a reduced yield.

COMPARATIVE EXAMPLE 2

[0125] [Production of Color Filter]

[0126] A color filter provided with a colored layer-laminated spacer wasproduced by sequentially patterning a resin black matrix and coloredlayers on a non-alkali glass substrate in substantially the same manneras in Example 1.

[0127] [Production of Color Liquid Crystal Display Device]

[0128] An ITO film was mask-formed on the color filter by sputtering.The ITO film had a film thickness of 1500 Å, and a surface resistance of20 Ω/□. A polyimide-based film was formed on the ITO film, and subjectedto rubbing.

[0129] A transparent electrode base plate equipped with TFTs wasproduced as described below.

[0130] First, a chrome film was formed on a transparent non-alkali glasssubstrate (OA-2 by Nippon Denki Glass Kabushiki Gaisha) by vapordeposition. Gate electrodes were patterned in the chrome film byphotoetching. Then, a silicon nitride (SiNx) film was formed to athickness of about 5000 Å by plasma CVD, thereby forming an insulatingfilm. Subsequently, an amorphous silicon (a-Si) film and an SiNx film asan etching stopper film layer were serially formed. The etching stopperlayer of SiNx was patterned by photoetching. In this etching process,sites that contact spacer elements were left unetched so that SiNx layerelements having an average area per element of about 250 μm² wereformed. An n⁺a-Si for ohmic contact was formed and patterned, and a filmof transparent electrodes (ITO) that form display electrodes was formedand patterned. Further, aluminum was vapor-deposited as a wiringmaterial on the entire surface, and formed into drain electrodes andsource electrodes by photoetching. Using the drain and source electrodesas a mask, n⁺a-Si in the channel portions was removed by etching,thereby producing TFTs.

[0131] A polyimide-based alignment layer was formed on the base plateand subjected to rubbing, as in the color filter.

[0132] The color filter provided with the alignment layer was fixed tothe transparent electrode base plate equipped with TFTs, using asealant. A liquid crystal was then injected through an injection openingformed in the seal, by leaving the empty cell under a reduced pressure,then dipping the injection opening into a liquid crystal tank, and thenintroducing a normal pressure. After injection of the liquid crystal,the injection opening was sealed. A polarizing plate was then fixed tothe outside surface of the base plate, thereby producing a cell. In theliquid crystal display device thus produced, the spacer partiallycontacted the display electrodes of the TFT base plate and thereforecaused a short circuit between electrodes, thus producing bright spotdisplay defects.

COMPARATIVE EXAMPLE 3

[0133] A color filter was produced by substantially the same procedureas in Example 1, except that the pigment dispersing time duringpreparation of each colored layer was reduced to 10 minutes. The surfaceroughness of each colored layer was measured by a surface roughnesstester, providing a surface roughness of 0.020 μm.

[0134] Using the color filter, a liquid crystal display device wasproduced by substantially the same procedure as in Example 1. In theliquid crystal display device, display defects were caused byorientation failure in the liquid crystal.

[0135] The color filter of the present invention wherein a spacer formedby patterning resin layers is provided on a black matrix on a colorfilter base plate, and the liquid crystal display apparatus of thepresent invention that employs the color filter and is driven by lateralelectric fields, achieve various advantages as follows:

[0136] (1) Since the spacer does not exist in a pixel portion,deterioration of the display quality caused by light scatter andtransmission by the spacer is eliminated so that display contrast inparticular is improved.

[0137] (2) Since spacer elements are regularly fixed and arranged on theblack matrix and in a non-display area outside the screen area, the cellgap becomes uniform so that no display irregularity caused by gapinconsistency is exhibited.

[0138] (3) Since there is no need to provide transparent electrodes onthe color filter, the possibility of a short circuit between electrodeswhen the base plates are being joined is eliminated, thereby making iteasier to produce a color filter provided with a spacer.

1. A liquid crystal display apparatus comprising: a color filter baseplate having a transparent substrate, a black matrix and a colored filmof three primary colors provided on the transparent subsrate, anelectrode-carrying base plate provided with electrodes for applying anelectric field parallel to the color filter, and a liquid crystaldisposed therebetween, wherein a spacer is formed on the black matrix bypatterning a resin.
 2. A liquid crystal display apparatus according toclaim 1, wherein the spacer is formed by laminating colored films ofthree primary colors.
 3. A liquid crystal display apparatus according toclaim 1, wherein the colored film has a relative dielectric constantless than 4.5.
 4. A liquid crystal display apparatus according to claim3, wherein the colored film has a relative dielectric constant of 3.6 orless.
 5. A liquid crystal display apparatus according to claim 1,wherein the colored film has been directly subjected to orientationtreatment.
 6. A liquid crystal display apparatus according to claim 1,wherein the colored film has a surface roughness of 0.010 μm or less interms of Ra value.
 7. A liquid crystal display apparatus according toclaim 1, further comprising an overcoat film provided on the coloredfilm.
 8. A liquid crystal display apparatus according to claim 7,wherein the overcoat film is directly subjected to orientationtreatment.
 9. A liquid crystal display apparatus according to claim 7 orclaim 8 wherein the overcoat film has a surface roughness of 0.010 μm orless in terms of Ra value.
 10. A liquid crystal display apparatusaccording to any one of claims 7 to 9, wherein the overcoat film havinga relative dielectric constant of 4.5 or less.
 11. A liquid crystaldisplay apparatus according to claim 10, wherein the overcoat film has arelative dielectric constant of 3.6 or less.
 12. A color filteraccording to any one of claims 7 toll, wherein the overcoat film is apolyimide film or a polyimide siloxane film.
 13. A liquid crystaldisplay apparatus according to claim 1, wherein the black matrix is aresin black matrix formed by dispersing a light-shielding agent in aresin.
 14. A liquid crystal display apparatus according to claim 13,wherein the resin for the resin black matrix is a polyimide.
 15. Aliquid crystal display apparatus according to claim 1, wherein the resinfor the colored films of three primary colors is a polyimide.
 16. Aliquid crystal display apparatus according to claim 1, furthercomprising an electrically conductive transparent film formed on areverse side of the transparent substrate.
 17. A liquid crystal displayapparatus according to claim 16, wherein the electrically conductivetransparent film has a specific resistance of 2 kΩ·cm or less.
 18. Aliquid crystal display apparatus according to claim 16 or claim 17,wherein the electrically conductive transparent film has a lighttransmittance of 96% or more.
 19. A liquid crystal display apparatusaccording to any one of claims 16 to 18, wherein the electricallyconductive transparent film has a film thickness of 10 nm to 100 nm.